1. Field of the Invention
The present invention relates mainly to an absorbent article for absorbing and retaining a liquid waste such as menstrual blood and, more particularly, to an absorbent article having leakage preventing side walls on the two widthwise sides of the liquid receiving side.
2. Related Art
In the prior art, there have been a variety of absorbent articles including a sanitary napkin, a urine absorbing pad and a disposable diaper. These absorbent articles are demanded, when worn, for absorbing the liquid waste reliably in liquid absorbing layers so that the liquid waste may not leak to the outside of the absorbent articles. For this purpose, there is an absorbent article which is provided on the surface of the liquid receiving side with leakage preventing side walls extending longitudinally on the two widthwise sides.
In the general structure of the leakage preventing side walls of the prior art, a longitudinally extending hydrophobic sheet is jointed to the top sheet of the absorbent article, and an elastic member extending longitudinally of the absorbent article is jointed to the hydrophobic sheet. By the elastic shrinking force in the longitudinal direction of the elastic member, a curving force in the longitudinal direction is applied to the absorbent article, and the leakage preventing side walls are raised to the liquid receiving side of the absorbent article so that the menstrual blood or the like may be prevented from leaking sideways.
In Japanese Patent Laid-Open No.215244/1996, for example, there is disclosed an absorbent article, the leakage preventing side walls of which are made of a synthetic resin film formed into a non-planar shape. In this absorbent article, the leakage preventing side walls thus subjected to the non-planar treatment to form longitudinal wrinkles are brought into facial contact with the skin of a wearer.
However, this absorbent article of the prior art has been frequently unable to guide the menstrual blood or the like, as having blotted the surfaces of the leakage preventing side walls, reliably to the side of the liquid absorbing layer so that the wearer is made to feel a physical disorder with the menstrual blood residing on the leakage preventing side walls and to cause the sideway leakage. In the structure, as disclosed in Japanese Patent Laid-Open No.215244/1996, the wrinkled leakage preventing side walls come into facial contact with the skin of the wearer, so that the menstrual blood or the like is liable to stay between the wrinkles although the contacts between the skin and the leakage preventing side walls are satisfactory. In addition, the leakage preventing side walls with the menstrual blood residing thereon come into facial contact with the wearer to intensify the uncomfortable feel at the wearing time.
The invention has an object to provide an absorbent article which is enabled to improve the wearing feel and to prevent the sideway leakage effectively by making it easy to guide the blotting liquid to the side of the liquid absorbing layer thereby to suppress the stay of the menstrual blood or the like on the leakage preventing side walls.
According to an aspect of the invention, there is provided an absorbent article comprising:
a main body including a support sheet, a liquid absorbing layer laid on the support sheet, and a liquid-permeable sheet provided on a liquid receiving side of the main body and covering the liquid absorbing layer; and
leakage preventing side walls provided on two sides of the main body lying opposite one another in the widthwise direction and extending in the longitudinal direction, to have root ends jointed to the surface of the liquid receiving side and to have free ends positioned apart from the surface of the liquid receiving side,
wherein each the leakage preventing side walls is formed of at least one side wall sheet to have an inner sheet portion facing the widthwise inner side of the absorbent article and an outer sheet portion facing the widthwise outer side of the absorbent article, and
wherein the inner sheet portion are provided with holes leading to the inside of the inner and outer sheet portions.
In the absorbent article of the invention, the menstrual blood, urine or the like infiltrates, when it blots the surface of the side wall sheet forming the leakage preventing side wall, into the space between the inner and outer sheet portions from the holes so that it is guided as it is to the root end through the space between the inner and outer sheet portions. Therefore, the liquid having blotted the side wall sheet does not reside in the side wall sheet but can prevent the sideway leakage effectively. Moreover, in the case where the leakage preventing side wall is inclined with its free end directed toward the widthwise outer side so that the leakage preventing side wall comes into facial contact with the skin of the wearer, the liquid hardly stays on the surface of the side wall sheet to contact with the skin so that the absorbent article is reluctant to give an uncomfortable feel to the wearer.
For example, it is preferable that the inner sheet portion is corrugated and that the holes are formed in at least the ridges of the corrugations.
With this construction, the liquid can enter the space between the inner and outer sheet portions of the leakage preventing side wall from the holes. Moreover, when the liquid enters the space between the confronting inner and outer sheet portions from the holes, it is retained on the inner faces of the ridges of the side wall sheet or guided to the root end along the inner faces of the ridges, so that the liquid is reluctant to stay on the surface of the side wall sheet facing the skin of the wearer.
The side wall sheet may be formed of a nonwoven fabric which is made of hydrophobic fibers or made hydrophobic (i.e., subjected to a hydrophobic treatment), or a hydrophobic resin sheet. The side wall sheet may be given later natural corrugations by the shrinking force of an elastic member or the like, without providing corrugations in advance. However, the preferable side wall sheet is corrugated in the following manner.
For example, it is preferable that the inner sheet portion is provided at least in its portion with: the corrugations of which the ridges and valleys are extended from the root end to the free end and arranged regularly in the longitudinal direction; and a flat portion extending in a direction of crossing the ridges and valleys of the corrugations, and that the holes are formed in the boundary portion between the ridges of the corrugations and the flat portion.
With the corrugations being thus formed to extend at their ridges and valleys from the root end to the free end and with the holes being formed in the end portions of the ridges, the menstrual blood or the like infiltrates into those ridges from the holes and is guided to the root end along the inner faces of the ridges.
Here, the term xe2x80x9cflat portionxe2x80x9d means a smooth surface portion where the side wall sheet is never corrugated or is corrugated lower than the aforementioned corrugations.
For example, the holes may be formed by rupturing the side wall sheet when the corrugations and the flat portion are shaped. If the holes are formed by the rupturing method, they can be formed at the same step as that of corrugating the side wall sheet.
The flat portion may extend in the longitudinal direction, and an elastic member for exhibiting an elastic shrinking force in the longitudinal direction may be jointed to the flat portion between the inner and outer sheet portions.
For example, when the inner and outer sheet portions are formed by folding back the side wall sheet, the flat portion may be formed at the folded-back portion of the side wall sheet forming the free end of the leakage preventing side wall. In an alternative, the flat portion may be formed midway between the root end and the free end of the leakage preventing side wall. In another alternative, the flat portion may be formed midway between the root end and the free end of the leakage preventing side wall, and the leakage preventing side wall may be so bent at the flat portion that its portion extending from the bent portion to the free end may be directed to the widthwise outer side.
Moreover, it is preferable that the holes are formed in or in the vicinity of the root end of the leakage preventing side wall. With the holes being formed on the side of the root end of the leakage preventing side wall, the menstrual blood or the like, as guided into the space between the inner and outer sheet portions, is then guided from the holes on the root end side to the liquid-permeable sheet and further to the liquid absorbing layer.
In order to release the liquid, which has entered the space between the inner and outer sheet portions, reliably from the root end side to the liquid-permeable sheet, it is preferable that the leakage preventing side walls are jointed at the root ends either onto two side end portions of the liquid-permeable sheet, as extending outwardly of the liquid absorbing layer in the widthwise direction, or onto a central portion of the liquid-permeable sheet, as positioned between the two side end portions and over the liquid absorbing layer.
If the inner and outer sheet portions are made water-repellent at their inner faces confronting each other, the liquid having entered the space between the inner and outer sheet portions is promptly guided to the root end side.